This invention relates to novel pharmaceutical compositions and methods for treatment and prophylaxis of cancer, more specifically for carcinostasis, reinforcement of carcinostasis and prevention of carcinogenesis.
Up to now, several types of carcinostatic agents have been known. These include; alkylating agents which exhibit the carcinostatic activity by alkylating such biopolymers with indispensable roles as nucleic acids and enzymes, metabolic antagonists which inhibit metabolism of nucleic acids, mitotic poisons which affect biosynthesis of nucleic acids in the cell, carcinostatic antibiotics which exhibit cytocidal activity against the cells in rapid proliferation, carcinostatic compounds of plant origin, and hormones.
On the other hand, amphotericin B and the like have been investigated as carcinostasis-reinforcing agents which may exhibit effects on improvement in absorption of drugs with poor absorbability to cancer cells and thus enhance carcinostatic effects of carcinostatic agents such as bleomycin and adriamycin. However none of them have come to attain any notable effect.
Any of carcinostatic agents known from the prior art do not get rid of causing side effects, and few of them exhibit a satisfactory effect. Consequently, carcinostatic agents with improved characteristics have been needed. And there also have been needs for excellent carcinostasis-reinforcing agents in order to let carcinostatic agents express their full effects.
Meanwhile, there is a leading hypothesis that carcinogenesis may be triggered through two steps mediated by an initiator and a promoter. However, the mechanisms of carcinogenesis is not known in relation to their influences exerted upon human body in daily life. Thus, prevention of carcinogenesis can only be pursued by a trial-and-error method based on experiences. Consequently, the development of carcinogenesis-preventing agents has been far behind that of anti-cancer agents.
The criteria for carcinogenesis-preventing agents may be as follows.
First, carcinogenesis-preventing agents, in general, are required to possess greater safety than that required for anti-cancer agents, and they have to be totally free of side effects.
Secondly, they are required to be effective by oral administration so as to be administered easily in daily life.
Thirdly, they are required not only to be effective on particular experimental cancers but also to have a wide spectrum against various types of cancers which have actually the higher rate of incidence.
On the basis of aforementioned situation, the inventors have screened substances of sebum origin in order to find compounds which will be useful as agents for treatment and prophylaxis of cancer, assuming that the development of such agents should be started from the naturally and physiologically occurring "bio-substances" in the body of higher animals. As the result, some compounds that fulfill the aforementioned requirements were discovered.
These compounds have both carcinostatic and carcinostasis-reinforcing effects.
Moreover, they are thought to be useful for general prevention of carcinogenesis, for prevention of recurrence after completion of cancer treatment, for prophylaxis of occupational cancer and for prophylaxis in those who are hereditarily liable to certain cancers. Since the compounds of the present invention are chemically stable and can remain unchanged after cooking, they may be used as food additives and for functional foods or health foods. The compounds of the present invention are compounds which occur naturally in sebum, and they may, accordingly, be readily accepted by general people.